EP0100330B1 - Hydraulic control device - Google Patents

Abstract

A hydraulic control device consists of a housing, a control slide valve displaceable in a bore of the housing, and a control ring. Axial displacement of the control slide valve makes it possible to connect together or to disconnect various connecting lines depending upon the position of the valve. Located in an annular chamber, formed between a section of the housing bore and the control slide valve is a control ring arranged coaxially with the valve and guided displaceably thereupon. Valve seats are spaced axially from each other both in the housing bore and on the control slide valve. The control ring comprises inner mating surfaces and outer mating surfaces cooperating with the valve seats. Provided between the two valve seats in the control slide valve is a flow channel running therein which is closed at one end depending upon the position of the control ring. The latter is held by the pressure of the flowing medium in the appropriate closed position, but the changeover may be effected independently of the pressure since no axial forces are applied to the control slide valve by the flowing medium.

Description

The invention relates to a hydraulic control device having a housing and a control slide which can be displaced in a housing bore, two valve seats being formed in the housing bore with an axial spacing from one another, and a plurality of connecting lines which can be connected to one another or can be shut off, depending on the position of the control slide, in one between one Section of the housing bore and the control valve formed annular space coaxial to the control slide and slidably guided on this control ring is provided, which has at its end areas mating surfaces to the valve seats on the housing bore, and wherein two valve seats are provided on the control slide with an axial distance from each other and the control ring has, at its end areas, mating surfaces with these control slide valve seats, and furthermore directly adjoining the valve seats between the two control slide valve seats and to an axially extending channel in the control channel connecting openings are provided, and a connecting line opens into the annular space between the two valve seats in the housing bore and on both sides outside of these valve seats in annular spaces between the housing bore and the control slide and to the channel in the control slide (DE-B -1 296 909).

Directional valves control the start, stop and direction of flow of a pressure medium and ultimately determine the direction of movement or stopping position of a consumer (cylinder or hydraulic motor). Directional valves can be divided into two groups based on their design, on the one hand in the directional poppet valves and on the other hand in the directional spool valves. Directional poppet valves differ fundamentally from the directional spool valves in that they have a leak-free shut-off feature, which cannot be achieved with spool valves due to the required clearance between the piston and the housing. The seat element is usually a ball that is pressed in a starting position by a spring onto a valve seat. Such valves can be used for pressures up to 700 bar, but only for small designs (up to 6 mm nominal diameter). If there are several flow paths and several switching positions, several valve balls must also be provided. If there are several flow paths, several directional seat valves are usually assembled accordingly. Such seat valves are therefore only to be used up to a certain diameter of the valve seats and thus the control slide, since otherwise the necessary switchover force, which must take place against the prevailing hydraulic pressure, becomes too great.

The most commonly used principle of directional control valves is the directional spool valve. The advantages of this configuration lie in the relatively simple structural design, in a relatively high switching capacity and in particular in a large number of control functions. A control slide is slidably held in a housing bore, this control slide covering or releasing the connecting lines in the different positions. Hydraulic control units in the form of slide valves can only be used up to a maximum pressure of 350 bar.

A 2/2 and 3/2 way direct solenoid-operated poppet valve has already become known (DE-U-7817627), in which two valve seats are provided at a distance from one another in a housing bore, a control slide forming the valve body and Depending on the required passageways, the valve bodies come into contact with the corresponding valve seats. The closing pressure of these valves is increased by the action of the hydraulic pressure, but this additional pressure also counteracts when the valve is switched. To create a certain balance here, back pressures have to be built up, which can be achieved by the hydraulic pressure also being led to the opposite ends of the control spool. Such seat valves generally enable two and a maximum of three flow directions through these two switching positions.

Furthermore, a multi-way valve has become known (DE-B-12 96 909), in which a control ring is held in the axial direction on the control slide. Both the valve seats and the mating surfaces on the control ring are arranged in radially aligned planes, so that there is always a relatively large area. Such large-area systems provide poor sealing, particularly at very high pressures. In the case of a printing medium, it is relatively common for minor impurities to be trapped, and with such mating surfaces, the smallest parts that get between the areas to be sealed cause a leak. It is therefore absolutely necessary in such an arrangement that the side surfaces of the control ring, here the two lateral ring parts in this known embodiment, are made from an elastically resilient material. However, this creates the risk that proper wear and tear of the mating surfaces is not ensured. In addition, such a seal with resilient parts is not suitable for high pressures.

Valves of this type are therefore suitable for a maximum pressure of up to approximately 35 bar. For pressures of 1000 bar or more, the sealing problems are much greater, in which case the sealing stops on the control slide are kept very small in order to be able to move the control slide with relatively little effort.

In such an embodiment, it is particularly difficult with the There are mating surfaces because practically every valve circuit uses a different surface, especially since this control ring is not guided exactly on the control slide, but can move slightly in the radial direction. There is therefore a relatively large amount of play between the control ring and the surface of the control slide.

The present invention has for its object to provide a hydraulic control unit in which the advantages of slide valves can be optimally combined with those of the seat valves, so that very high pressures can be managed regardless of the size and also the required switching force is independent of pressure .

For this purpose, it is proposed according to the invention that the control ring has outer conical fitting surfaces and inner funnel-shaped fitting surfaces at its end regions, that the outer fitting surfaces are larger in area than the inner fitting surfaces on the control ring, that the distance between the valve seats on the control slide valve is greater than the distance between the valve seats in the Housing bore, the length of the control ring is smaller than the distance between the two valve seats on the control slide, that the valve seats on the housing bore and on the control slide are limited by cylinder surfaces and radial planes running in the axial direction, and that between the two control slide valve seats directly to the valve seats in the displacement area of the control ring connecting and leading to the axially extending channel in the control channel connecting openings are provided.

It is only through the measures of the present invention that proper sealing is ensured even at high pressures and also with a large number of switchovers. Precisely due to the linear contact of the seat surfaces with the valve seats, it is also not possible for a leak to be caused by the ingress of contamination. The special arrangement of the connection openings to the channel in the control slide means that the diameter difference between the guide area of the control ring and the valve seats on the control slide can be kept small, and that the valve seats also have the necessary stability since they are not, as in the known design , must be designed to be freely cantilevered over a relatively large area and can therefore always be made in one piece with the adjacent part of the control slide. Due to the smallest possible differences in diameter, a relatively small construction of the control slide including the control ring is possible despite the required valve seats on the control slide.

The measures according to the invention, namely that the length of the control ring is smaller than the distance between the two valve seats on the control slide and that the distance between the valve seats on the control slide is greater than the distance between the valve seats in the housing bore, ensures that in the released area between the control ring and the valve seat on the control slide, at least the same flow opening remains free as in the area between the control ring and the relevant valve seat on the housing. An essential difference between the known embodiment and the present invention can also be seen in the fact that sealing edges are formed in each case and not, as in the known embodiment, sealing surfaces, since such sealing surfaces do not ensure a reliable seal at high pressures. In addition, both the valve seats and the corresponding mating surfaces on the control ring can be made of a suitable, non-flexible material in order to be able to transmit the necessary contact pressures easily. With the arrangement of flexible seals there are always problems with high pressures. In the case of mating surfaces made of flexible material, there is a cold flow in this material, so that the valve path becomes larger after each sealing process in order to achieve a seal again. It is therefore not at all possible with such designs to use them at high pressures, as is the case with a construction according to the present invention.

The measures according to the invention also ensure that, on the one hand, the control ring provided is held in the corresponding closed position by the pressure of the medium being carried out, but that the hydraulic control device can be switched to a different switching position regardless of the pressure. No pressure forces emanating from the medium carried through act on the control slide itself in the axial direction, so that in order to adjust this control slide, the slight force of a possibly existing compression spring or the pressing force of the seals only has to be overcome at least in one displacement direction. However, as soon as the control slide is moved slightly, an annular gap is opened between the corresponding inner fitting surface of the control ring and the associated valve seat on the control slide, so that the pressure is immediately reduced or there is the same pressure on both sides of the control ring, so that at a further adjustment of the control slide, the control ring can be pushed without additional effort until it in turn arrives in the opposite switching position.

Seat valves are thus created by the invention in which the switching force is independent of pressure, so that such hydraulic control devices can also be used with a correspondingly large diameter of the housing bore and the control slide and thus with large flow rates. Nevertheless, the advantages of a slide valve are achieved in that a 4/2-way valve, that is to say a valve with four flow directions and two switching positions, can be created. Such a hydraulic control device is for very high Pressures are suitable regardless of the size, whereas seat valves of conventional design are only suitable for high pressures with a small nominal diameter. Such high pressures are not manageable with slide valves.

Despite relatively simple constructive measures, a hydraulic control device can be created which can be switched independently of pressure and which can be used for very high pressures and also for large passages.

The present invention thus brings a significant advance over the known designs since, despite the simple construction and simple and pressure-independent switching operations, use for the highest pressures and for small and large passages is possible.

Details of the invention are explained in more detail in the following description with reference to the drawings. 1 to 3 show horizontal sections through a hydraulic control device according to the invention; Figures 4 and 4a are schematic representations of the possible paths through the hydraulic control unit. 5 shows an enlarged view of the area surrounding the control ring compared to FIGS. 1-3; 6 is an oblique view of the valve housing with the hand pump attached; 7 is a view of the pump housing; 8 to 10 sections along the lines I-I, 11-11 and 111-111 in Fig. 7; Fig. 11 is a side view of the pump housing.

The hydraulic control unit essentially consists of a housing 1, a control slide 2, a control ring 3, and the connecting lines A, P, B and T.

The housing 1 is made in two parts and consists of a base body 4 and a tubular insert 5, this measure being necessary for design reasons. This insert 5 is fixedly arranged in the base body 4, a locking ring 6 being used for the position which is secure against displacement. Several sealing rings 7, 8 and 9 or packs are inserted between the base body 4 and the insert 5. The housing 1 formed from the base body 4 and the insert 5 includes a housing bore 10 which is stepped down several times. On this housing bore 10, two valve seats 11 and 12 arranged at an axial distance from one another are provided, here again for reasons of simpler construction, the valve seat 11 is formed by the base body 4 of the housing 1 and the valve seat 12 by the insert 5. So that there is sufficient wall thickness for insert 5, the two valve seats 11 and 12 have different diameters, but it would be quite conceivable that these two valve seats 11 and 12 are designed with the same diameter. In this embodiment, the valve seats 11 and 12 are limited by cylindrical surfaces extending in the axial direction, which are formed by the housing bore 10, and radial planes 13 and 14. This results in correspondingly sharp-edged valve seats.

The insert 5 of the housing 1 is designed with a closed base 15, so that the housing 1 is closed to the outside.

The control slide 2 is axially displaceable in the housing 1, which is guided in a front section 16 of the base body 1 and in the bore 17 of the insert 5. Sealing rings 18 and 19 are also used here for sealing at the end regions of the control slide. On this control slide 2, two valve seats 20 and 21 are provided at an axial distance from one another, which are limited on the one hand by the lateral surface of the control slide and on the other hand by radial surfaces guided radially inwards. Between these two valve seats 20 and 21, connection openings 22 and 23 are provided, which lead to a channel 24 extending in the axial direction within the control slide 2. This channel 24 is open towards the one end of the control slide and opens there into a space 25 enclosed by the insert 5.

As can be seen from the drawing, the distance between the valve seats 20, 21 on the control slide 2 is greater than the distance between the valve seats 11 and 12 in the housing bore 10. A greater displacement path of the control slide valve is thereby possible despite a small displacement path of the control ring 3, whereby nevertheless, there is sufficient flow of the medium through the connection openings 22 and 23 at the respective end positions.

The control slide 2 is formed from two components 26 and 27 which follow one another in the axial direction and are firmly connected to one another, each component 26 and 27 having one of the two valve seats 20 and 21. In a structurally simple manner, a section 28 with a smaller diameter than the remaining area of the control slide 2 can be created between the two valve seats 20 and 21. As a result, not only can the valve seats 20 and 21 be produced in a simple manner, but also the guide for the displaceable control ring 3. The two components 26 and 27 are connected in a simple manner by screwing, the end of the component being shown in the exemplary embodiment shown 27 with a threaded bolt and the corresponding end of the component 26 with a threaded bore. By mutual centering surfaces, the two components 26 and 27 are exactly aligned with each other.

In the context of the invention, it is possible for the actuation-side component 26 of the control slide 2 to be flared towards its end on the control ring side. This can be a very small conicity, for example the difference in diameter over a length of approximately 1 cm is approximately 0.1 mm.

As a result, the one closed position of the control ring and the control slide can be supported by the hydraulic pressure, since the control slide is held in the operating position in this direction against the force of the spring 29 got to. The stop position is thus supported by the hydraulic pressure, with the taper being able to go so far that the spring force is practically canceled or the force on the control slide is somewhat greater than the counteracting spring force. A slight push is then only required to loosen the valve or to switch to the other position. Nevertheless, the spring 29 then acts correspondingly strongly in the other switching position.

When actuated by an electromagnet, the spring 29 can of course also be omitted, since the necessary switching force is brought about by these electromagnets. So that a corresponding contact pressure on the valve seats is ensured in both directions, there is therefore the possibility that the areas adjoining the valve seats 20 and 21 on both sides taper conically at least over a short section towards the respective end of the control slide 2. Again, it can be provided that the difference in diameter over a length of e.g. 1 cm is approximately 0.1 mm. The correspondingly thicker areas of the control slide 2 can then pass directly into the valve seats 20, 21. This ensures that a corresponding closing pressure is present in both end positions of the control slide and thus also of the control ring. In order to adjust the spool against this closing pressure, only minimal forces are required, e.g. can be easily applied by an electromagnet or by hand.

In the context of the invention, however, it is also possible for a collar which has a slightly larger diameter than the control slide 2 to be connected directly in the region of a valve seat 20 or 21 or also for both valve seats 20 and 21. This also makes it possible to achieve a low closing pressure, which, however, can in turn be easily overcome when switching operations are necessary.

In the space 25 inside the insert 5, a compression spring 29 is inserted, which is supported on the one hand on the bottom 15 of the insert 5 and on the other hand on the end face 30 of the control slide 2. The control slide 2 is thereby held spring-loaded in the position shown in Fig. 1. When the hydraulic control device is switched over, only the force of this spring 29 therefore has to be overcome.

The control ring 3, which is held displaceably on the section 28 of the control slide 2, coaxially encloses the control slide 2 and is designed with outer fitting surfaces 31 and 32 and with inner fitting surfaces 33 and 34, which have the corresponding valve seats 11 and 12 or 20 and 21 interact. These mating surfaces 31 and 34 are formed on the end regions of this control ring 3, the outer mating surfaces 31 and 32 being conical and the inner mating surfaces 33 and 34 funnel-shaped. This creates a tight seal between the valve seats and the mating surfaces, so that even very high pressures can be safely shut off.

The outer fitting surfaces 31 and 32 are larger in area than the inner fitting surfaces 33 and 34, so that this control ring 3 can be designed as a symmetrical turned part, although the two valve seats 11 and 12 have a different diameter. Furthermore, the length of the control ring 3, viewed in the axial direction, is smaller than the distance between the two valve seats 20 and 21 on the control slide 2, but larger than the distance between the two valve seats 11 and 12 on the housing bore 10. As a result of the larger diameter, there are external Valve seats 11 and 12 have larger passage areas when the passage is open, so that less displacement is required as a result. In addition, the displacement range on the control slide is therefore chosen to be larger in order to achieve a sufficient opening of the through openings 22 to the channel 24.

The control ring 3 is thus inserted into an annular space 35 remaining between the housing bore 10 and the control slide 2, the arrangement of such an annular space 35 and further annular spaces 38, 45 providing simple options for supplying the connecting lines A, P, B and T. The connecting line P, through which the pressure medium is supplied, opens into the annular space 35 in the area between the two valve seats 11 and 12. On both sides outside of these valve seats 11 and 12, the connecting lines A and B open, the connecting line A opening into the annular space 45 and the connecting line B being fed via an annular channel 36 and connecting channels 37 to the annular space 38 left free between the control slide 2 and the insert 5. The connection line T, which serves as a return line to a storage tank, opens out via an annular channel 39 and one or more radial feed openings 40 into the space 25 within the insert 5 and is thus connected to the channel 24 within the control slide 2.

In the above description it was mentioned that the valve seats 11 and 12 or 20 and 21 represent sharp-edged sections. Of course, it is possible to provide a slight chamfer here.

In the exemplary embodiment shown, the control slide 2 is adjusted by a hand lever 41 which is rotatably mounted on the housing 1 about the axis 42. One arm 43 of the lever 41 comprises a bolt 44 on the free end region of the control slide 2.

4 that the hydraulic control device according to the invention represents a 4/2-way valve, the individual switching positions being shown schematically in this figure. So there is the possibility to connect the connecting line P with the connecting line B and at the same time the connecting line A with the connecting line T. Furthermore, there is the possibility of connecting all four connecting lines A, B, P, T to one another in an intermediate position. In the second switching position, the connecting lines A and P as well as B and T are each connected to one another.

The workflow and the individual positions of the hydraulic control device will now be explained in more detail with reference to FIGS. 1 to 3. Such a hydraulic control device can be used, for example, to control a hydraulic piston which has to be adjusted in both directions by the pressure medium. It is therefore necessary on the one hand to supply the pressure to one side of the hydraulic piston and on the other hand to discharge the hydraulic medium from the opposite side of the hydraulic piston. When the hydraulic piston moves in the opposite direction, the feed and the discharge are required in the opposite direction.

In the position according to FIG. 1, the control ring 3 rests with its fitting surface 31 on the valve seat 11 and with its fitting surface 34 on the valve seat 21. The control slide 2 is in its rest position caused by the spring 29. In this position of the control slide 2 and the control ring 3, the pressure medium supplied through the connecting line P can be fed along the outside of the control ring 3 to the annular space 38, from where it reaches the connecting line B via the connecting channels 37 and the annular channel 36. At the same time, in this position, the connecting line A is connected to the connecting line T, starting from the connecting line A via the annular space 45, the connecting opening 22, the channel 24, the space 25, the supply opening 40 and the annular channel 39, so that the returned medium can in turn be returned to the storage tank. The contact of the control ring 3 on the two valve seats 11 and 21 is effected by the spring 29 and is also supported by the force of the pressure medium acting on the control ring 3 in the axial direction.

If the hydraulic control unit is now to be switched over, the control slide 2 can be adjusted in the axial direction by actuating the hand lever 41, the displacement according to the invention being able to take place independently of the pressure, i.e. no axial force due to the pressure medium acts on the displacement movement of the control slide 2. As soon as the control slide 2 is moved a corresponding distance, the valve seat 21 moves away from the mating surface 34 of the control ring 3, so that through the connection openings 23 there is an immediate pressure relief of the pressure medium supplied through the connection line P, since a connection to the unpressurized connection line T is created . This position is shown in Fig. 2, where all the connecting lines A, P, B and T are connected to each other.

By moving the control spool 2, the valve seat 20 then comes to rest on the mating surface 33 of the control ring 3, so that it is carried in the direction of adjustment of the spool 2 until the mating surface 32 then comes to rest on the valve seat 12. In this position, the connecting line P is then connected to the connecting line A and through the connecting line B the returned medium can be led to the connecting line T and thus to the storage tank. The pressure now built up in the area of the connecting lines P and A and in the annular spaces 35 and 45 supports the closing movement of the control ring 3, although the hand lever 41 must be held in this position. For short-term circuits, however, this is readily possible, since only the force of the spring 29 has to be overcome.

Even when this position is released, there are again no problems due to an axial pressure effect of the medium on the control ring 3, since the control slide 2 can be adjusted independently of the pressure, the connection opening 22 being exposed after a short displacement path and pressure being reduced.

Within the scope of the invention it is of course also possible to provide a different type of actuation for the control slide instead of a hand lever 41. It would be quite conceivable to actuate the control slide 2 by other mechanical means or also hydraulically, pneumatically or electrically or electromagnetically, in which case the spring 29 is of course not absolutely necessary.

In the above description it was mentioned that the housing is designed in two parts in that a base body 4 and an insert 5 are provided. Of course, there is also the possibility of producing this housing, seen in the axial direction, from two sections, which are then connected to one another by axially parallel screws. It would also be possible to provide a threaded connection, namely by providing a threaded hole in one housing part and a threaded ring on the other housing part. In such an embodiment, a series of ring channels could be omitted, which must be provided for sealing between a base body 4 and an insert 5. It would therefore only be necessary to appropriately seal the control slide at its two output ends.

In the exemplary embodiment shown, the connection openings 22 and 23 are designed as radial bores which are arranged directly adjacent to the valve seats 20 and 21, these bores being inclined at an acute angle to the connection-side end of the channel 24, in order thereby to achieve better flow conditions. Of course, there is also the possibility of providing continuous slots between the valve seats 20 and 21 instead of the individual connecting openings 22 and 23. It would also be possible to use the inner boundary surface of the control ring 3 or on the surface of section 28 of the control slide 2 grooves are provided, which are then optionally connected to the channel 24 by additional arrangement of an annular channel via corresponding connection openings. In all these cases, there is the possibility of creating a connection opening to the channel 24 immediately after a valve seat 20 and 21 has been moved away from the corresponding mating surface 33 or 34 of the control ring 3. In addition, the opposite side is then given sufficient passage for the return of the unpressurized medium.

Of course, further design changes are possible within the scope of the invention, but two valve seats arranged at a distance from one another must always be provided both on the control slide 2 and on the housing bore 10 and a control ring which can be displaced in the axial direction on the control slide 2. Of course, the supply of the individual connecting lines is correspondingly conditioned by the construction according to the invention.

Various other possibilities can be integrated in the valve housing 1, it being precisely through these measures that the possible uses of the hydraulic control device according to the invention can be increased or improved. For example, it is possible to use pressure reducing valves in the valve housing 1 between the connection lines A and B to the consumers and / or the connection line P for supplying the pressure medium and the return connection line T to the storage tank. This is particularly advantageous if different pressures are required in the two connecting lines A and B. It would be possible, for example, to deliver the pressure medium at a pressure of 1,000 bar by means of an arranged pump, with a pressure reduction to 800 bar in the direction of one pressure circuit and a pressure reduction to 300 bar in the direction of the other pressure circuit. Such pressure relief valves can be set permanently or can also be set variably.

Furthermore, an unlockable double check valve can be assigned to connection lines A and B, the check valve of the other connection line B or A being unlockable by building up pressure in one connection line A or B. The switching positions and passageways resulting here can be seen in the schematic illustration in FIG. 4a. This can be achieved, for example, by a double-acting piston, which opens the check valve provided on the unpressurized side with its protruding sensors. As a result, the range of application of the hydraulic control device can be expanded considerably, since this provides a positive overlap of the two valve positions. There is therefore no longer a complete pressure equalization in the middle position, which is particularly important for hydraulic drives or lifting equipment.

6 shows an embodiment of the hydraulic control unit in which a pump housing 46 is connected to the housing 1. The special design of the hydraulic control unit makes it possible to flange-mount such a pump housing 46 directly, since the connection lines for the supply of the pressure medium and the drain line to a storage tank can be provided at the correspondingly desired locations. Corresponding connecting lines D and E are then provided on the pump housing 46. It is therefore only necessary to use an appropriate seal when flange-mounting such a pump housing, after which there is a tight connection without intermediate line after tightening the fastening screws.

Such a pump housing can be seen in FIGS. 7 to 11, it being evident that this pump housing is designed in a simple construction as a one-piece metal block, only corresponding bores having to be provided. On the one hand, this is a bore 47 for the pump plunger 48 and on the other hand, these are bores 49, 50 and 51 running transversely to this bore 47 for the connecting lines as well as for check valves 60 and 61. A pump housing 46 can therefore be created solely by making various bores can be flanged to a hydraulic control unit in a simple manner. In this pump housing a threaded bore 52 is also inserted, into which a bearing body 53 can be screwed. This bearing body 53 serves for rotatably receiving a hand lever 54 which is connected to the pump tappet 48 via a coupling element 55 and a bolt 56.

The valve bodies in the pump housing 46 can be designed in a simple manner as spring-loaded ball check valves 60, 61. Both the non-return valve 61 provided in the intake line and the non-return valve 60 acting as an outlet valve are designed as ball seat valves, the non-return valve 61 having the valve seat 62 inserted loosely, a seal being provided by a sealing ring 63. After screwing together with the valve body, this valve seat 62 can no longer protrude from the bore 49. In the check valve 60, a bolt 65 is provided to support the spring 64 and is sealed with respect to the bore 51 by means of a sealing ring 66. In a transverse bore 67 of this bolt 65, a locking pin is inserted through the bore 68.

Furthermore, two connection lines P and T can be provided on the valve housing 1 for the supply of pressure medium and for the discharge into the storage tank, with the pump housing 46 for manual operation on one connection line and a motor-operated pump on the other connection lines P, T can be connected. 6 also shows two screw heads 57 and 58 which can be used for setting pressure reducing valves or, for example, pressure relief valves in the valve housing 1.

The construction according to the invention thus made it possible to create a hydraulic control device which brings with it substantially better, safer and larger possible uses than previously known.

Although the description speaks of a hydraulic control device, the constructions according to the invention could be used in the same way for pneumatic control devices.

Claims (18)

1. Hydraulic control valve having a housing (1 ) and a control slide valve (2), which is displaceable in a housing bore (10), two valve seats (11, 12) being formed in the housing bore (10) at an axial distance from one another, and a plurality of connection lines (A, P, B, T), which may be connected to one another or reciprocally blocked in dependence upon the position of the control slide valve (2), a control ring (3) which is arranged coaxially relative to the control slide valve (2), and which is displaceably guided on the said control slide valve being provided in an annular chamber (35), which is formed between a section of the housing bore (10) and the control slide valve (2), which control ring comprises, at its end regions, fitting surfaces (31, 32) for the valve seats (11, 12) on the housing bore (10), and two valve seats (20, 21) arranged at an axial distance from one another being provided on the control slide valve (2), and the control ring (3) comprises, at its end regions, fitting surfaces (33, 34) for the said seats (20, 21 ) for the control slide valve, connection openings (22, 23) being provided in addition between the two seats (20, 21) of the control slide valve and being directly connected to the valve seats (20, 21) and leading to a duct (24), which extends axially in the control slide valve, and a connection line (A, P, B, T) opens in each case into the annular chamber (35) between the two valve seats (11, 12) in the housing bore (10), and on both sides outside the said valve seats (11, 12) into annular chambers (38, 45) between the housing bore (10) and the control slide valve (2), and into the duct (24) in the control slide valve (2), characterised in that, at its end regions, the control ring (3) comprises outer bevelled fitting surfaces (31, 32) and inner funnel- shaped fitting surfaces (33, 34), the outer fitting surfaces (31, 32) have a larger surface area than the inner fitting surfaces (33, 34) on the control ring (3), the distance between the valve seats (20, 21 ) on the control slide valve (2) is greater than the distance between the valve seats (11, 12) in the housing bore (10), the length of the control ring (3) being smaller than the distance between the two valve seats (20, 21) on the control slide valve (2), the valve seats (11,12), (20, 21 ) on the housing bore (10) and on the control slide valve (2) are defined by cylindrical surfaces and radial planes (13, 14) extending in an axial direction, and connection openings (22, 23) are provided between the two seats (20, 21) of the control slide valve, which connection openings are directly connected to the valve seats (20, 21 ) in the displacement area of the control ring (3) and which lead to the duct (24) extending axially in the control slide valve.

2. Hydraulic control valve according to claim 1, characterised in that the connection openings (22, 23) are formed in the control slide valve (2) as radial bores, which are arranged between the two valve seats (20, 21) and which are directly connected to the valve seats (20, 21 ).

3. Hydraulic control valve according to claims 1 and 2, characterised in that the connection openings (22, 23) formed as bores are acute-angled relative to the end of the duct (24) which is on the side of the connection lines.

4. Hydraulic control valve according to claims 1 and 2, characterised in that the connection openings in the control slide valve (2) are formed as through slots between the two valve seats (20, 21).

5. Hydraulic control valve according to claims 1 and 2, characterised in that the connection openings in the control slide valve (2) are formed by longitudinal grooves provided between the valve seats (20, 21 ) on the control slide valve (2) or on the inner bore of the control ring (3), and bores, which lead to the duct (24) and which are provided between the valve seats (20, 21) on the control slide valve (2).

6. Hydraulic control valve according to claims 1 to 5, characterised in that the duct (24), which is open at one end of the control slide valve (2), opens into a chamber (25) formed by a housing bore, and a spring (29) for axially loading the control slide valve (2) is provided in the said chamber (25).

7. Hydraulic control valve according to claims 1 to 6, characterised in that the control slide valve (2) is formed by two component parts (26, 27), which are consecutive in an axial direction, and which are securely connected to one another, each component part (26, 27) comprising one of the two valve seats (20, 21 ).

8. Hydraulic control valve according to claim 1 and any one of the preceding claims, characterised in that the housing (1) is formed in two parts, one part of the housing bore (10) being formed by a tube-shaped insert (5), and the said insert (5) comprises one valve seat (12) and the housing part of the other valve seat (11), which part is formed as a basic body (4).

9. Hydraulic control valve according to claim 8, characterised in that the valve seat on the basic body (4) of the housing (1) has a larger diameter than the valve seat (12) on the insert (5) of the housing (1).

10. Hydraulic control valve according to claim 1 and any one of the preceding claims, characterised in that pressure reducing valves are integrated in the valve housing (1) between the connection lines (A, B) to the comsuming devices and/or the connection line (P) for the supply of the pressure medium and the return connection line (T) to the storage tank.

11. Hydraulic control valve according to claim 1 and any one of the preceding claims, characterised in that a double reversing valve, which may be opened, is associated with the connection lines (A, B), the reversing valve of one connection line (A, B) being opened as a result of a build up of pressure in the other connection line (A, B) in each case.

12. Hydraulic control valve according to claim 1 and any one of the preceding claims, characterised in that regions of the control slide valve (2), which are connected to the valve seats (20, 21), taper, at least over a short section, in the direction of the respective end of the control slide valve (2), the difference in the diameters over a length of, e.g., 1 cm being approximately 0.1 mm.

13. Hydraulic control valve according to claim 1 and any one of the preceding claims, characterised in that a shoulder, having a slightly larger diameter than the control slide valve (2), is connected to the region of the control slide valve (2) which is directly connected to one, or both, valve seat(s) (20,21).

14. Hydraulic control valve according to claim 1 and any one of the preceding claims, characterised in that a pump housing (46) is directly connected to the connection lines (P, T) for the supply of the pressure medium and the return line to a storage tank.

15. Hydraulic control valve according to claim 14, characterised in that the pump housing (46) is screwed flat onto the valve housing (1), the connection lines (P, T) of the valve housing (1) corresponding directly with the suction line (E) or the pressure line (D) of the pump housing (46).

16. Hydraulic control valve according to claims 14 and 15, characterised in that the pump housing (46) is formed as a one-piece metal block having a bore (47) for the pump push rod (48), and bores (49, 50, 51) extending transversely to the first bore (47) for the connection lines (D, E) and the valve bodies.

17. Hydraulic control valve according to claims 14 to 16, characterised in that the valve body in the pump housing (46) is formed as a springloaded ball retaining valve.

18. Hydraulic control valve according to claim 1 and any one of the preceding claims, characterised in that, two connection lines (P, T) are provided in each case on the valve housing (1) for the supply of pressure medium and for the return to the storage tank, a pump housing (46) being connected to one connection line (P, T) for manual operation and a motor-driven pump being connected to the other connection line (P, T).

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